SpaceX’s Crew Dragon capsule utilizes several integrated systems to provide thermal regulation for astronauts during all phases of flight. A liquid-based Thermal Control System (TCS) with pumps and exterior radiators maintains cabin air and component temperatures within a habitable 10-46°C range. An independent Vapor Compression System air conditioner turns on after parachute deployment to control humidity and augment cooling without exchanging cabin air. Fans and ducts actively circulate internal atmosphere to avoid stagnant pockets. Insulation on the capsule exterior protects against extreme heat and cold of space.
The TCS includes two separate fluid loops with pumps that circulate coolant to regulate equipment heat loads and reject excess warmth via ammonia radiators mounted on the capsule’s unpressurized trunk section. The radiators face deep space and shed heat through their large surface area. Control valves and mixing modes optimize heat transport for various thermal environments. Triple-redundant sensors monitor loop health. If off-nominal performance occurs, the TCS can reconfigure to secondary components.
An air conditioning system based on a hydrofluorocarbon refrigeration cycle provides additional temperature and humidity control after parachute deployment through docking/recovery. Fans blow cabin air across evaporator coils then return dehumidified, cooled flow back to the crew compartment without direct ventilation to the outside. This protects astronauts in the event of propellant leaks post-landing.
Air revitalization for breathability comes from circulation rather than active oxygen generation or carbon dioxide removal. Fans and ducts throughout the cabin continuously pull atmosphere across HEPA filters and charcoal scrubbers then route it back through vents, aided by the convection of crew body heat. One Inter-Module Ventilation duct also draws in fresh air from the International Space Station when docked. Airflow prevents pockets of stagnation and meets minimum velocity requirements set by NASA across specified cabin volumes.
The capsule pressure vessel and underlying structure are wrapped in thick, multi-layer insulation blankets that resist conductive and radiative heat transfer. Windows allow crew visibility and optical calibration of thermal imagers but are treated to reject infrared wavelengths. The ablative heat shield composed of SpaceX’s PICA-X tiles provides additional protection during atmospheric entry. Hundreds of sensors feed telemetry to ground control for performance monitoring.
Crew Dragon’s thermal control results from the integrated design of its capsule insulation, triple-closed liquid cooling loops, air conditioning refrigeration, atmosphere circulation fans, and ablative reentry shielding. These robust, redundant systems maintain safe 10-46°C temperatures through all mission environments from pre-launch to post-landing. Their reliability has been demonstrated across multiple flights since 2020.
